Blue Sea Systems Tech Tip: Fuse Color Coding Explained

Color coding made easy. Make sure you use the correct fuse. Learn how here ...read more

Circuit protection color coding helps boaters to match fuses with compatible fuse holders and fuse blocks in order to improve interpretation. On the packaging for fuse holders and fuse blocks, there will be color coded labels in the form of rectangles that will be an indicator designed for each specific holder or block. Some fuse blocks will require multiple fuse types. Some of the more well-known ratings appear in blue or black. The blue consists of APS, ATO, or ATC ratings, and the black consists of AMI and MIDI. These are not the only ratings. However, there are many other classifications. Below is a representation of the required fuse types. The stats on these ratings are as follows:

-APS: micro2, micro3, and low-profile mini

-APM/ATM: mini

-APR/ATC/ATO: regular

-APX: maxi (heavy duty)

The sizes on these are as follows:

ATR:

Length: 9.1 mm

Width: 3.8 mm

Height: 15.3 mm

ATL:

Length: 14.4 mm

Width 4.2 mm

Height: 18.1 mm

APS/ATT:

Length: 10.9 mm

Width: 3.81 mm

Height: 8.73 mm

APM/ATM:

Length: 10.9 mm

Width: 3.6 mm

Height: 16.3 mm

APR/ATC/ATO:

Length: 19.1 mm

Width: 5.1 mm

Height: 18.5 mm

APX:

Length: 29.2 mm

Width: 8.5 mm

Height: 34.3 mm

We do recommend advising with a local mechanic or technician to determine what size and rating you need for your application. read less